964 resultados para CUTICULAR LIPIDS
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Foods derived from animals are an important source of nutrients for humans. Concerns have been raised that due to their SFA content, dairy foods may increase the risk of cardiometabolic disease. Prospective studies do not indicate an association between milk consumption and increased disease risk although there are less data for other dairy foods. SFA in dairy products can be partially replaced by cis-MUFA through nutrition of the dairy cow although there are too few human studies to conclude that such modification leads to reduced chronic disease risk. Intakes of LCn-3 FA are sub-optimal in many countries and while foods such as poultry meat can be enriched by inclusion of fish oil in the diet of the birds, fish oil is expensive and has an associated risk that the meat will be oxidatively unstable. Novel sources of LCn-3 FA such as kirll oil, algae, and genetically modified plants may prove to be better candidates for meat enrichment. The value of FA-modified foods cannot be judged by their FA composition alone and there needs to be detailed human intervention studies carried out before judgements concerning improved health value can be made. Practical applications: The amount and FA composition of dietary lipids are known to contribute to the risk of chronic disease in humans which is increasing and becoming very costly to treat. The use of animal nutrition to improve the FA composition of staple foods such as dairy products and poultry meat has considerable potential to reduce chronic risk at population level although judgements must not be based simply on FA composition of the foods.
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Crude enzymes produced via solid state fermentation (SSF) using wheat milling by-products have been employed for both fermentation media production using flour-rich waste (FRW) streams and lysis of Rhodosporidium toruloides yeast cells. Filter sterilization of crude hydrolysates was more beneficial than heat sterilization regarding yeast growth and microbial oil production. The initial carbon to free amino nitrogen ratio of crude hydrolysates was optimized (80.2 g/g) in fed-batch cultures of R. toruloides leading to a total dry weight of 61.2 g/L with microbial oil content of 61.8 % (w/w). Employing a feeding strategy where the glucose concentration was maintained in the range of 12.2 – 17.6 g/L led to the highest productivity (0.32 g/L∙h). The crude enzymes produced by SSF were utilised for yeast cell treatment leading to simultaneous release of around 80% of total lipids in the broth and production of a hydrolysate suitable as yeast extract replacement.
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Lipidomic analyses of milling and pearling fractions from wheat grain were carried out to determine differences in composition which could relate to the spatial distribution of lipids in the grain. Free fatty acids and triacylglycerols were major components in all fractions, but the relative contents of polar lipids varied, particularly lysophosphatidyl choline and digalactosyldiglyceride, which were enriched in flour fractions. By contrast, minor phospholipids were enriched in bran and offal fractions. The most abundant fatty acids in the analysed acyl lipids were C16:0 and C18:2 and their combinations, including C36:4 and C34:2. Phospholipids and galactolipids have been reported to have beneficial properties for bread making, while free fatty acids and triacylglycerols are considered detrimental. The subtle differences in the compositions of fractions determined in the present study could therefore underpin the production of flour fractions with optimised compositions for different end uses.
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Patterns of the biosynthesis ofmajor metabolites of the oleaginous yeast Cryptococcus curvatus NRRL Y-1511 were investigated during cultivation on sugar-based media. When lactose or sucrose was employed as substrate under nitrogen-limited conditions, the yeast strain accumulated high quantities of intra-cellular total sugars (ITS) at the beginning of fermentation (up to 68% w/w), with ITS values progressively decreasing to 20%, w/w, at the end of the fermentation. Decrease in ITS content and consumption of extracellular lactose led to a subsequent rise in lipid accumulation, reaching 29.8% in dry cell weight at 80 g/L of initial lactose concentration. Lactose was a more favorable substrate for lipid production than sucrose. In nitrogen-excess conditions, ITS were produced in significant quantities despite the continuous presence of nitrogen in the medium. Growth on lactose was not followed by secretion of extra-cellular b-galactosidase. High quantities of extra-cellular invertase were observed during growth on sucrose. The composition of ITS was highly influenced by the sugar used as substrate. Cellular lipids contained mainly palmitic and to lesser extent linoleic and stearic acids. This is the first report in the literature that demonstrates the interplay between the biosynthesis of intra-cellular total sugars and lipid synthesis for oleaginous yeast strains.
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Background and aims: Virgin olive oil (VOO) and nuts are basic components of the Mediterranean diet, a heart-healthy dietary pattern. Nuts have well known cholesterol lowering effects, while evidence is unclear for VOO. We designed a study in hypercholesterolemic patients to assess the effects on serum lipids and other intermediate markers of cardiovascular risk of replacing 40% of the fat in the background diet with VOO, walnuts or almonds. Methods and Results: After a 4 week run-in period with a healthy diet, eligible candidates were randomized into three diet sequences in a crossover design, with a common background diet enriched with VOO, walnuts or almonds, lasting 4 weeks each. Outcomes were changes of serum lipids and oxidation and inflammation markers, measured by standard methods. Plasma fatty acids were determined by gas chromatography to assess compliance. In 18 participants completing the study (9 women, mean age 56 y, BMI 25.7 kg/m(2)), LDL-cholesterol was reduced from baseline by 7.3%, 10.8% and 13.4% after the VOO, walnut and almond diets, respectively (P = 0.001, Friedman test). Total cholesterol and LDL/HDL ratios decreased in parallel. LDL-cholesterol decreases were greater than predicted from dietary fatty acid and cholesterol exchanges among diets. No changes of other lipid fractions, oxidation analytes or inflammatory biomarkers were observed. Plasma fatty acid changes after each diet sequence supported good compliance.
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Background: ABCA1 plays an important role in HDL metabolism. Single nucleotide polymorphisms (SNPs) in ABCA1 gene were associated with variation in plasina HDL-c. Methods: The effect of the ABCA1 SNPs C-14T, R219K and of a novel variant C-105T on serum lipids was investigated in 367 unrelated Brazilian individuals (224 hypercholesterolemic and 143 normolipidemic). The relation between ABCA1 SNPs and the lipid-lowering response to atorvastatin (10 mg/day/4 weeks) was also evaluated in 141 hypercholesterolemic (HC) individuals. The polymorphisms were detected by PCRR_FLP and confirmed by DNA sequencing. Results: Linkage disequilibrium was found between the SNPs C-105T and C-14T in the HC group. HC individuals carrying - 105CT/TT genotypes had higher serum HDL-c and lower triglyceride and VLDL-c concentrations as well as lower TG/HDL-c ratio compared to the -105CC carriers (p<0.05). The R219K SNP was associated with reduced serum triglyceride, VLDL-c and TG/HDL-c ratio in the HC group (p<0.05), and with an increased serum apoAI in NL individuals. The effects of ABCA1 SNPs on basal serum lipids of HC individuals were not modified by atorvastatin treatment. Conclusions: The ABCA1 SNPs R219K and C-105T were associated with a less atherogenic lipid profile but not with the lowering-cholesterol response to atorvastatin in a Brazilian population. (C) 2007 Elsevier B.V. All rights reserved.
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Background: The SR-BI is a key component on the cholesterol metabolism. Polymorphisms in the SR-BI gene (SCARB1) were related with variations on plasma lipoprotein profile and other risk factors for cardiovascular disease. We tested the relationship of 3 SCARB1 single nucleotide polymorphisms (SNPs) with hypercholesterolemia in a Brazilian population and whether these variants can influence lipid-lowering response to atorvastatin. Methods: c.4G>A, c.726+54C>T and c.1050C>T SNPs and serum concentrations of lipid and apolipoproteins were evaluated in 147 hypercholesterolemic (HC) and 185 normolipidemic (NL) unrelated Brazilian subjects. HC patients were treated with atorvastatin (10 mg/day/4 weeks). Results: Frequencies of SCARB1 polymorphisms were similar between the HC and NL groups (p>0.05). The T allele for c.726+54C>T was associated with higher LDL-c in NL and with higher apoB and apoB/apoAI in HC (p<0.05). HC individuals carrying c.1050C allele carriers (CC and CT genotypes) had lower change of total cholesterol, LDL-c, apoB and apoB/apoAI ratio (p<0.05) than the TT genotype carriers in response to atorvastatin. Conclusion: The SCARB1 polymorphisms are related with variations in serum lipids in the Brazilian population and c.1050C>T SNP is associated with lipid-lowering atorvastatin response. (C) 2010 Elsevier B.V. All rights reserved.
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Camarea is a South-American endemic genus comprising eight species. In the present work n-alkanes from foliar cuticular waxes of 23 specimens, representing seven species of Camarea were analyzed, aiming at establishing interspecific affinities and evaluating the usefulness of n-alkane distribution as species characteristic. The sampling included also specimens of Peixotoa rericulata and Janusia guaronitica (both Malpighiaceae). The results were used to obtain a phenogram indicating chemical affinities between species. The results are in agreement with morphological similarities among some Camarea species. Intraspecific variability was small, suggesting that n-alkane distribution may be useful for species characterization and establishment of links among Camarea species. The results support the recognition of Camarea triphylla as a synonym of Camarea axillaris and are not coherent with a hybrid condition of a population exhibiting morphological characteristics combining Camarea affinis and Camarea hirsuta, suggesting instead that the individuals analyzed belong either to Camarea hirsuta or a close species. Distribution of n-alkanes is inadequate to distinguish among Malpighiaceae genera: P reticulata has n-alkane distribution similar to several Cumarea species. (C) 2008 Elsevier Ltd. All rights reserved.
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The specialist digger wasp Trachypus boharti Rubio-Espina preys exclusively on males of the stingless bee Scaptotrigona postica Latreille 1807, although the hunting attacks involve both male and worker bees of S. postica and members of its own species. To understand the mechanism of prey selection, the cuticular hydrocarbon patterns of workers and males of S. postica are analyzed in detail, and the mandibular secretion of males is examined. The cuticular profiles of males and workers are distinctively different. The major group of cuticular compounds, heptacosene isomers, is twice as abundant in workers as in males. There is no clear distinction between worker and male mandibular secretions. Such a distinct and straightforward caste-specific difference in cuticular hydrocarbons could function as a recognition cue by which T. boharti distinguishes between workers and males of S. postica.
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Triplet-excited riboflavin ((3)RF*) was found by laser flash photolysis to be quenched by polyunsaturated fatty acid methyl esters in tert-butanol/water (7:3, v/v) in a second-order reaction with k similar to 3.0 x 10(5) L mol(-1) s(-1) at 25 degrees C for methyl linoleate and 3.1 x 10(6) L mol(-1) s(-1), with Delta H double dagger = 22.6 kJ mol(-1) and Delta S double dagger = -62.3 J K(-1) mol(-1), for methyl linolenate in acetonitrile/water (8:2, v/v). For methyl oleate, k was <10(4) L mol(-1) s(-1). For comparison, beta-casein was found to have a rate constant k similar to 4.9 x 10(8) L mol(-1) s(-1). Singlet-excited flavin was not quenched by the esters as evidenced by insensitivity of steady-state fluorescence to their presence. Density functional theory (DFT) calculations showed that electron transfer from unsaturated fatty acid esters to triplet-excited flavins is endergonic, while a formal hydrogen atom transfer is exergonic (Delta G(HAT)degrees = -114.3, -151.2, and -151.2 kJ mol(-1) for oleate, linoleate, and linolenate, respectively, in acetonitrile). The reaction is driven by acidity of the lipid cation radical for which a pK(a) similar to -0.12 was estimated by DFT calculations. Absence of electrochemical activity in acetonitrile during cyclic voltammetry up to 2.0 V versus NHE confirmed that Delta G(ET)degrees > 0 for electron transfer. Interaction of methyl esters with (3)RF* is considered as initiation of the radical chain, which is subsequently propagated by combination reactions with residual oxygen. In this respect, carbon-centered and alkoxyl radicals were detected using the spin trapping technique in combination with electron paramagnetic resonance spectroscopy. Moreover, quenching of 3RF* yields, directly or indirectly, radical species which are capable of initiating oxidation in unsaturated fatty acid methyl esters. Still, deactivation of triplet-excited flavins by lipid derivatives was slower than by proteins (factor up to 10(4)), which react preferentially by electron transfer. Depending on the reaction environment in biological systems (including food), protein radicals are expected to interfere in the mechanism of light-induced lipid oxidation.
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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)
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Objective: HIV infection is exacerbated through additional pro-atherogenic mechanisms related to the processes of immune activation, inflammation, coagulation, and the modification of lipoproteins (e.g., particles of high density lipoprotein), contributing to increased cardiovascular risk. The aim of this study was to analyze the serum concentrations of myeloperoxidase (MPO) and other laboratory parameters in HIV-infected patients treated or not with antiretroviral drugs compared to non-infected individuals.Materials/Methods: The study included 154 volunteers: 47 non-infected individuals (control group - CON), 27 infected and untreated individuals (NTARv group) and 80 treated individuals (TARV group). We analyzed the counts of CD4+ lymphocytes and the viral load of the infected patients, along with the blood count, fasting glucose, total serum cholesterol (CHOL), HDL cholesterol, LDL cholesterol, triglycerides, MPO and high-sensitivity C-reactive protein (CRP) of all study participants.Results: There were significant increases in glucose, CHOL, LDL cholesterol, and triglycerides in the TARV group and significant reductions in the levels of HDL cholesterol for the TARV and NTARV groups. Significantly elevated levels of Hs-CRP were observed only in the TARV group, while levels of MPO were significantly higher in the TARV and NTARV groups compared to the control group. A correlation of MPO with Hs-CRP (r = 0.21, p = 0.032) was observed for HIV-infected patients, but MPO did not correlate significantly with the other analyzed parameters.Conclusions: The investigation of early biomarkers for cardiovascular risk evaluation, such as MPO, contributes to the clinical monitoring of HIV-infected individuals. The serum levels of MPO correlated with Hs-CRP and were high in HIV-infected individuals, indicating a possible predictor of cardiovascular events in these patients. (c) 2012 Elsevier B.V. All rights reserved.
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)